1. Technical Field
The present invention relates to a media processing device that continuously conveys plural media through a conveyance path from a media supply unit to a paper exit past a processing position where the media is processed, and to a control method of the media processing device.
2. Related Art
JP-A-2003-72964 discloses a printer having a paper cassette that stores plural sheets of printing paper; a conveyance path passing the print position of the printhead to the paper exit; a paper supply mechanism that delivers the printing paper from the paper cassette to the conveyance path; and a conveyance mechanism that conveys the printing paper fed into the conveyance path through the conveyance path. In the printer in JP-A-2003-72964, the printing paper fed into the conveyance path by the paper supply mechanism is conveyed through the conveyance path by the conveyance mechanism and printed on as it passes the print position, and the printed paper is then discharged from the paper exit. The paper supply mechanism feeds a new sheet of paper from the paper cassette before the paper already being conveyed through the conveyance path is discharged from the paper exit. This improves the throughput of continuous printing when printing continuously on plural sheets of paper.
If the paper supply mechanism feeds multiple sheets of paper at the same time from the paper cassette, the conveyance mechanism feeds the overlapping sheets at the same time through the conveyance path. This is a problem known as double-feeding. To prevent double-feeding, the printer disclosed in JP-A-2009-7106 has a paper separating mechanism (also known as a retard mechanism) at the upstream end of the conveyance path in the conveyance direction.
The paper separating mechanism disclosed in JP-A-2009-7106 has a separating roller and a paper return lever. This separating roller is generally called a retard roller, and is pressed against a second conveyance roller of the conveyance mechanism disposed at the upstream end of the conveyance path. The separating roller applies a load to the printing paper passing the nipping part with the second conveyance roller, separating and passing only one sheet of paper from the plural sheets of double-fed paper. After the sheet of paper separated by the separating roller passes the nipping point, part of the paper return lever protrudes into the conveyance path and returns the paper that did not pass through the nipping point to the paper cassette side.
The paper return lever returns the excess sheets to the paper cassette side as a result of being set to a paper return position where part of the lever protrudes into the conveyance path. Before supplying the next sheet of paper starts, the paper return lever is preferably set to a retracted position removed from the conveyance path to that the lever does not interfere with the paper fed from the paper cassette to the conveyance path.
The separating roller, however, must be set to the pressure position pressed against the second conveyance roller before the supply operation starts, and is preferably set to a retracted position separated from the second conveyance roller so that the separating roller does not interfere with the paper return operation of the paper return lever after the single sheet passes the nipping point.
A printer or other media processing device having a paper return lever and a separating roller therefore preferably also has an operating mechanism that moves the paper return lever and the separating roller in conjunction with each other, and performs a retard retard preparation operation that moves the paper return lever from the paper return position to the retracted position, and moves the separating roller from the retracted position to the pressure position, position, before the paper supply operation is performed by the paper supply mechanism.
If the drive power of the moving mechanism that moves the paper return lever and the separating roller comes from the paper feed motor that drives the conveyance mechanism, the manufacturing cost of the device can be suppressed. However, if the moving mechanism and the conveyance mechanism share the same drive source, the retard preparation operation of the moving mechanism and the paper feed operation of the conveyance mechanism work at the same time, and starting starting the retard preparation operation at a separate desired timing timing is difficult. If the retard preparation operation cannot be started at the desired timing, the paper supply operation of the supply supply mechanism cannot be executed at the desired time, and adjusting the interval between two sheets of paper fed consecutively through the conveyance path appropriately to print modes of different print resolutions is difficult.